Break-back implement attachment for tractors



Aug; 29, 1950 w. H. TANKE 2,520,743

BREAKBACK TMPLEMENT ATTACHMENT FOR TRAcToRs Filed Oct. 24, 1946 2Sheets-Sheet 1 INVENTOR @zum m. Mm BY U TTORNEY Aug. 29, 1950 w. H.TANKE BREAKBACK IMPLEMENT ATTACHMENT FOR TRACTORS Filed 061'..v 24, 19462 Sheets-Shea?l 2 INVENTOR` www 2%. BY

ATTORNEY Patented Aug. 29, 1950 BREAK-BACK IMPLEMENT ATTACHMENT FORTRACTORS v Willard H. Tanke, La Crosse, Wis., assignor toAllis-'Chalmers Manufacturing Company, Milwaukee, Wis., a corporation ofDelaware Application October 24, 1946, Serial No. 705,452

Claims.

This invention relates in general toimplement attachments for tractors,and it is concerned more particularly with break-back implements, thatis, with implements of the type which under normal operating conditionsare retained in a desired working position with reference to a tractorand which may be advanced by the latter in said position, and which areso arranged that under emergency conditions, for instance, when theimplement is driven in said Working position against an obstructionbeyond which it cannot be advanced by the tractor, the implement maypivot rearwardly relative to the tractor, or in other words, break-backfrom said working position, in order to avoid damage of the implement.

The prior art includes implements of the above mentioned character,particularly tractor mowers, which are equipped with break-backmechanisms of the releasable latch type, that is, of the type in which alatch element and a complementary locking element are arranged to snapinto cooperative engagement with each other upon ad.- justment of theimplement into a normally desired working position relative to thetractor, so that the implement may be advanced by the tractor in saidnormally desired working position, and so that under abnormal workingconditions, as when the implement in its normal working position isdriven against an obstruction, the latch element and its complementarylocking element may snap out of cooperative engagement with each otherand thereby release the implement for break-back movement relative tothe tractor.

In break-back mechanisms of the mentioned character the latch is apt totrip under a lighter or heavier load, depending on the condition or" themechanism as determined by wear, rust, presence or absence of lubricant,and other causes which are di'icult to control. The lack of precisionresulting from these causes has been found objectionable, particularlyin tractor mowers where it has been observed that when the latch tripstoo easily, careless operators sometimes resort to tying up the latchwith a piece of baling wire or otherwise permanently locking it, so thatthe latch cannot trip at all. Gn the other hand, in instances where thelatch had become impeded, as by the formation of rust, and the implementwas driven against an obstruction, tripping of the latch required such astrong force that the implement was damaged upon striking anobstruction.

Generally, it is an object of the invention to provide an improvedbreak-back arrangement for tractor implements which are horizontallyswingable from a working to a non-working position, and moreparticularly to provide a break-back. mechanism for such implements thatwill function reliably and with a high degree of precision, first, toprevent premature or accidental release of the implement under normalworking conditions and, second, to promptly release the implement forbreak-back movement under emergency conditions as when the implement inits normal working position is driven against an obstruction beyondwhich it cannot be advanced by the tractor. v

A further object of the invention is to provide a break-back mechanismof the above mentioned character which will permit reconditioning of theimplement for normal operation, after a break-back, by simply drivingthe tractor a short distance in reverse.`

A further object of the invention is to provide an improved break-backmechanism for tractor implements, which willl reliably function in themanner set forth hereinbefore and which, after the implement has beenreleased for break-back movement, will function to dampen such breakbackmovement and assist return of the implement into its normal workingposition.

A further object of the invention is to provide an improved tractormower incorporating a break-back mechanism which will permit movement ofthe cutting mechanism of the mower from a normal working position into arearwardly inclined non-working position, and which breakback mechanismwill not be apt to develop substantial wear which would require frequentreadjustment in order to maintain the break-back mechanism in properworking condition.

These and other objects and advantages are attained by the presentinvention, various novel features of which will be apparent from thedescription herein and accompanying drawings disclosing an embodiment ofthe invention, and will be more particularly Apointed out in the claims.

In the drawings:

Fig. 1 is a top view of a trailing type breakback mower and of the rearend of a conventional type tractor connected with the mower;

Fig. 2V is a side view of the tractor and mower assembly shown in Fig.1;

Fig. 3 is an enlarged top view of a break-back mechanism incorporated inthe mower shown in Figs. l and 2; and

Eie- 4 is a rear viewy of theY mechanism shown in Fig. 3 and taken inthe direction of arrow A.

Referring to Figs. 1 and 2, right and left rear wheels I and 2,respectively, of a conventional type tractor are mounted on a rear axlestructure comprising aV central gear casing 3, hollow side arms l! andS, and final drive casings 'I and depending, respectively, from theouter ends of side arms 4.- and 6 and on which the rear wheels aremounted inv axial alignment with. each other. A rearwardly arched drawbar 9 is mounted at its opposite ends on the nal drive casings I and, 8,respectively, by means of aY pivot pin I I and a bolt I2, as indicatedin Fig. 2, connecting; eachV end of the draw bar with the adjacent iinaldrive casing and securing the draw bar. against vertical, displacementrelative to the. tractor body from the position in which the draw bar isshown in Fig. 2. A power take-off mechanism. including a power take-offshaft I3 is mounted in the central gear casing 3 and is operable by the.tractor motor in conformity with conventional practice, the powertake-off.` shaft t3. being rotatable. about a horizontal. axis extendinglongitudinally of the tractor and. centrallybetween the rear wheels Iand 2.

|The mower: shown in Figs. 1r and 2 in rear of the tractor is of thesemi-mounted type, `that is, it isr equipped with a forward hitchstructure by which it is; partly sustained on the tractor, and with arear support. by which it is partly sustained on the ground andindependently of the tractor;

The forward. hitch structure for connecting the mower insupportedrelation to the tractor comprises a bracket I4 and a hitch barlIii which are hingedly connected with each. other by means of; two:pivot bolts If'II and I'8 at opposite ends, respectively, of the`bracket i4. The bracket I4. is form-odor a piece of strap metal-, theopposite ends of whichA are turned'Y up and provided with holes formounting of the bolts Isl and I8,w and the straight portion of thebracket between its upturned ends: has a pair ofv holes for thereception of fastening bolts I8- and- 2,I-' which are Vpassed through.said holes and through registering holes in: thev draw bar 9 so as: todetachably secure the bracket inv a; transversely and vertically xedposition on the tractor. Thehitch bar I6 is likewise formed of a pieceof strap metal which isbent.v into U--shape to provide forwardlyextending ear portionsA which straddlethe bracket Ill and' have: alignedholes for' the reception of the bolts- H and' I3. rLhe hitch' barA I-eis thus connected with thetractor for pivotal movement about ahorizontal transverse axis and intransversely fixed relationY to thetractor, and the bolts H- and I8 are suitably retained on the bracket leto provide for free pivotal. movement of the hitchbar 4Il about thecommon axis of the bolts: t? and I8; Y

The hitch bar; 'It carries a U-shaped bracket 22 Fig. 2, which isYrigidly secured, as by welding, to the hitch bar- Ib Fig. 1 in*vproximityi tol the rig-ht end of the latter, that is; in` proximity tothe end ofthe hitch bar I6 which is' connected' to the bracket Id by thebolt Il. .The-bracket' 22 is; formed@ of strap: metal and' extends atright anglesto the hitch' bar I.- The portioniof the bracket 22'extending upwardly from the hitch it has a ben-t upperportion projectingrearwardly beyond the hitch bar" It, andthe portion of-thes bracketA 22extendingdownwardly from the. hitch bar If5 has a similarly bent lowerportion projecting rearwardly beyond the hitch bar' l5- Hingedlyconnected to the rearwardly projecting. upper and lower portions4 Qf thebracketv Y of a diagonal rod d6.

22 by means of pivot bolts 23 and 24, as best shown in Fig. 2, isanother bracket 2B which is substantially a duplicate of the bracket 22,an upper portion of the bracket 26 overlying the upper portion of thebracket 22 and having a hole in registry with a hole in the upperportion of the bracket 2/2- for the reception of the bolt 23, and thelower bent portion of the bracket 26 overlying the lower bent portion ofthe bracket 22 and having a hole in registry with a hole in the lowerbent portion of the bracket 22 for the reception of the bolt 24. Thebolts 23 and 24 are axially aligned with each other, and the bracket 2'3is thus mounted for swinging movement about an axis in transversely xedrelation to the tractor.

Thebracket 25 forms part of the frame structure ofthe mower, and it isrigidly secured, as by welding, to the forward end of a longitudinalframe member 2l' which consists of a straight piecev of square tubingVand extends in right angle Vrelation to the pivot. axis afforded by thebolts 2t and. 25. Y At its rear end the tubular frame. member 2lrcarries rearwardly extending bracket straps 2i?` and 29 for mounting iton a castering wheel support comprising a wheel 3i and a wheel fork 32which has a spindle portion 33 rotatably: mounted in the bracket straps28 and 29.

Rig-idly secured to the frame member 2?, intermediate its front andyrear ends, is a depending bracket structure 3d'. Fig. 2 to whichV a dragarm 36 Fig. l is pivotally connected by means of a long pivot pin 3i,the axis of the pivot pin 31 being disposed, generally parallel to theframemember 2l' and the drag arm 36 being freely swingable about saidaxis. Mounted onthe outer end of the drag arm, 313 in conventionalmanner isa cutter bar yoke 38- which forms part of a conventionalcutting mechanism comprising a cutter bar 3Q, a reciprocable sickle barfil, and an inner shoe. 5.12, the inner shoe 42 being pivotallyconnected with the cutter bar yoke 38 by means' of' frontrand rearpivots i3v and M, as best shown inV Fig. 2; The yoke 33 is additionallyconnected with the frame structure of the mower by means- Apair of straplugs 4l and- S are welded to a lower portion of the bracket 26,;andcarry a pivot pinV 49 which extends through anv eyeon the inner end ofthe rod 45. The cutting mechanism is thus connected with the framestructure of the mower for movement in unison with the latter about theforward' pivot axis affordedby the bolts 23 andy 24.

Also mounted on the depending bracket structure 3d is a flywheel 5lwhich. carries a crank pin 5-2. A pitman 53,V is connected with thecrank pin 52 and with the sickle bar it in conventional manner order toreciprocate the sickle bar upon rotation of the flywheel 5I. A bearingtube 54 for the shaft of .the flywheel 5I is rigidly mounted Yon thebracket structure Sii and a driv-` ing sheave 5tY for theflywheelshaftis arranged at the rear side of the bracket structure 54 asshown in Figs. 1 and 2.

At. the left. side. of the frame tube 2l, that is, at the side thereofremote from the cutting mechanism, another bracket structure 5l Fig. 1is mounted onv the frame tube- 2l and carries a bearing tube 58Y for anyupper drive shaft 59. A

p sheave ti is. secured to the upper drive shaft 59 forwardly of thebracket structure 5l andy in alignment with the sheave 5t on the lowerbracket structure 3d, the' two sheaves being drivingly connected witheach other by a belt 52.

The' cutting mechanism may be raised and lowered by pivotal movement ofthe cutter bar 39 relative to the yoke 38 about the pivots 43 and 44 andby pivotal movement of the drag arm 36 relative to the mower frame aboutthe axis of the pivot pin 31, in conformity with conventional practice,and a suitable mechanism, not shown, may beprovided for that purpose andarranged in any convenient manner. For transport purposes, the cutterbar 39 may be swung upwardly about the pivots 43 and 44 Fig. 2 on theyoke 38 and retained in an upwardly tilted position by a rod 63 which isshown in Figs. l and 2 and which may be moved from the position in whichit is shown in these figures into an attaching position with the cutterbar 3S in order to hold'the latter in an upright transport position. Therod 63 is looped to a stud 8| on the frame member 21, and as shown inFigs. 1 and 2, rests in a slot of the bracket strap 28.

Fig. 1 shows the mower in two positions behind the tractor, one, in fulllines, which is the normal working position of the mower relative tothetractor and in which the cutter bar shoe 42 oatingly rides on theground, and another position, in dotted lines, in which the frame andthe cutting mechanism are angularly displaced relative to the tractorabout the axis of the pivot bolts 23 and '24 so that the cuttingmechanism occupies a rearwardly inclined non-working position.` Thefront end of the mower frame 21 is connected to the hitch bar I6 bymeans of the pivot bolts 23 and 24 in proximity to the right end of thehitch bar I6, as stated hereinbefore, and .it will be'noted that in thenormal working position of the mower @the cutting mechanism,

comprisingthe cutter bar 39 and the sickle bar 4I, is disposed at oneside of the frame member 21 whereas the portion of the hitch bar I6which extends to the left of the bracket 22 is disposed at the otherside of the frame member 21.

' A spring actuated toggle mechanism is operatively interposed betweenthe hitch bar I6 andthe frame member 21 for the purpose of releasablymaintaining the cutting mechanism in the normal working position inwhich it is shown in full lines in Fig. l. Referring to Figs. 3 and 4, arelatively long toggle link generally desig nated by the referencecharacter 64 comprises two parallel identical bars 66 which are arrangedone above the other and secured together in spaced relation to eachother by spacers 61 and rivets 68. 'A second, relatively short togglelink generally designated by the reference character 69 comprises twoparallel and identical bars 1I which are arranged one above the otherand secured together in spaced relation to each other by spacers 12 andrivets 13. The outer surfaces of the bars 1! are spaced from each othera slightly shorter distance than the inner surfaces of the bars 66, andthe short toggle link 69 is straddled by the bars 66 of the long togglelink 64 and is pivotally connected thereto by means of a pivot bolt 14which is surrounded by a spacer bushing 15. The free end of the shorttoggle link 69, remote from the pivot 14, is pivotally mounted in aU-shaped bracket 16 by means of a pivot bolt 11. The bracket 16 has twooblong holes 18 Fig. 4 in its bottom portion for the reception of twomounting bolts 19 which extend through the hitch bar I and are tightenedso as to secure the bracket in fixed position on the hitch bar i6. Theoblong holes 18 permit adjustment of the bracket 16 longitudinally ofthe hitch bar I6 in order vto provide for horizontal anglingof the framemember 21 relative to the 6*j hitch bar I6, as will be discussed morefully hereinbelow.

Referring to Fig. 2, it will be noted that the hitch bar I6 and thebracket 16 are arranged in such vertical relation to the frame member 21that the latter is located at a higher level than the bracket 16. Thefree end of the long toggle link 64 remote from the pivot pin 14 extendsunder the frame member 21 and is pivotally con nected therewith by astud 6I which extends vertically through the frame member 21 and isrigidly secured thereto, as 'by welding. The downwardly projectingcylindrical portion of the stud 8| extends through aligned holes in theupper and lower bars 66 andcarries anut 82 at its lower end to securethe toggle link 64 against axial separation from the stud 8|.

Designating the pivotal connection between the frame 21 and the hitchbar I6 by means of the pivot bolts 23 and 24 as a first pivot center,and the pivotal connection between the toggle links 64 and 69 at 14 as asecond pivot center, and further designating the pivotal connection ofthe short toggle link 63 with the hitch bar i6 at 11 as a third pivotcenter and the pivotal connectionl of the long toggle link 64 with theframe 21 at 8l asa fourth pivot center, it will be noted that in theposition of they toggle mechanism as shown in full lines in Figs. 1 and3,"said second pivot center at 14 occupies a position in close proximityto a line through the third and fourth :pivot centers 11 and BI. In thementioned full line position, the toggle links 64"and 59 are disposed ata slight angle relative to each other, which is preferably about threedegrees, and the toggle links are prevented from moving into dead centerrelation, that is, into exactA alignment with each other, by stops 83which are formed, respectively, on the upper and lower bars 1I oftheshort toggle link 69 and which are laterally abuttable with the spacer61 of the long link 64, next to the pivot i4, as best shown, in Figs. 3and 4. In other words, engagement of the stops 8-3 with the mentionedspacer 61 determines the toggle position in which the links 64 and 69are shown in full lines Vin Figs. l and 3, and while the rlinks 64 and69 are prevented by said engagementv of the stops 83 with the mentionedspacci` 61 from overtraveling said toggle position they are free'tobreak away from said toggle position into the folded position in whichthey are shown in dotted lines in Figs. l and 3.

It will be further noted thatv in the toggle position of the links whichis determined by engagement of the stops 83 with the mentioned spacer 61the second pivot center at 14 is located in rear of a line through thethird and fourth' pivot centers at 11 and 8i, that is, at the Side ofsaidr line remote from said first p-ivot center at 23.

The toggle links 64 and 69 are urged into the toggle position in whichthey vare shown. in full lines in Figs. l and 3 by a coil spring 84which is anchored at one end thereof on the intermediate spacer 61 ofthe toggle link 64 and at the other end on a U-bolt 86 which mounted onthe hitch bar IS intermediate the vbrackets 22 and 16. The

vision of the bracket 16 on the hitch bar Iii-affords assuma E areaction point for the toggl'ejlinky trans.- versely fixed relation tothe tractor and ata1 pre.-A determined. horizontal'. distance from thefirst pivoaccnten atl 23'.. The vertical stud el. on'the frame.' member2'1" provides; a reaction point for the' toggle link 64' on the. frame21 in horizontally spaced relation to the rst pivot. center` at 23,.andthe'toggle mechanismis automatically 'operatine.A to establish a;bracing: connection betweensaid reaction .points upon horizontal'swinging movement of the 2T: into the predetermined angular positionrelative, to the; tractor in which itis shown' in full? lines. in Figs.1 and. 3. Upon establishment of, said bracing connection the' togglelinks: function. asfl a compression brace-f between the frame member'l'lr and the hitchbar l in order to maintain the' cutting' mechanismin. its. normale working position'. The toggle. mechiurtherautomatically operative to disable. saidf bracing connection under'certain conditions, namely, when the frame 21. becomes subject tofaturning force which subjects the frame to horizontal; swingmg' movementabout the firsty pivot center at'. 23' in a directionr to shorten thespacing'bctween' the reaction points at 1.1 and 8 l and parti'cuiarlywhen such turning force exceeds. a. certain' limit which isv determined'by' the tension: of the spring 84'.

The toggle mechanism is arranged in such a manner as stated, that' when'the cutting mechanism is located; in its normal working position,air-'shown in' lines', the second pivot center at 'bt is located inclose.; proximity to the deadcenter` line through' the pivot connectionat TT om the hitclr bar I-IS and; the. pivot connection at at. on; theframe 211, and'. said arrangement' further enables.'l said' togglemechanism to: exert a relatively' high resistance against swingingIncrementar die frame 21 andthe cutting mechanism 38'-, 4l' from. thefull` line position shown in: Eig'. 1'. into the dotted linev positionin` which the cutting mechanism occupies: a rearwardly inclinednon-working` position.. This initial resistance may be. adjusted' byincreasing. or decreasing thetension'of thefcoilspring 84, that is,byadjustment oi the nuts' 8T on= the U-bofltY B6.

When the cutter' bary 39, in its normal working' position', is drivenagainst an obstruction be-v yondi which iticannot'be advanced bythetractor,

as' for instance' against a rock or vfence post, the

resulting' increased thrust upon the toggle links 64 and B9 will causethe latter to break away fromtheir rul'lline toggle position towards thefolded position which is indicated' i'n dotted lines in 1' and'. 3During such movement of" the toggle links thel coil spring' 84 will besomewhat elongated and, as a result', the coill spring will dampen thebreak-back movement of the cutting mechanism. Such break-back movementoi the cutting mechanism may4 continue until the toggle. f

link 69 hits a stop 83 which isV secured to the. hitch bar t6" at the,left end.. of the. latten, that is, at the endthereof. which isconnected to the. bracket Ml. by means of the. pivot bolt i8. In. orderto reconditionthe mower for normal operation, after abroak-back,V it. isonly necessary to drive, the tractor for a shortV distance in reversewhile the. cutting mechanism isA left in contact with the ground. Vfhilethe frame andV cutting mechanism are being manipulatedfrom the dashedline position` toV the full line position shown. in Eig.. l', byIvreverse. movement of the tractor, the tension of the coil spring 84 willbe efiec.tive'.i tm assist suche return movement of the & frame andcutting'mechanism into the normali operating position..

When the. cutting mechanism isc raised to.z an uprighttransport-position, as has been mentioned; hereinbefore; the weight' orthe cutting-.mechanism subjects the frame to:- a. lateral' tilting loadwhich; tends. to.i displace the: frame torsionally relative. to; thehitch' bar' t6. Under' these and: conditions which may arise during`operation of' the mower, the lateral tilting load'` is.- transmitted tothe hitch bar t6 not only throughE the pivot; boltsv 23 and but. also.`throirgfl'l the; toggle linksl 6.4, 6&1. In other words, the.y togglemechanism functions to stabilize; the frame. against torsionakdisplacement: relative'I to: the. hitch: bar |23', and said. stabilizingfunction of' the: toggle mechanisme is obtained` by' mounting' thelinks. 5.9' andi 614,. as: described hereinbeiore', in horizontallyswingable and vertically non-swingablerelation, to each other' and; tothe: hitch bar: l5 and frame member I1H',respectively. A

As; stated hereiI-Ibelora1 the bracket; it :tor the' short toggle link.d'9 i's' adjustable.- longitudinallyl of the hitchbar' i6 in order' toprovide fortiori.- zonta-l angling of the frame member Ztl relative' tothe hitchV barV l-Sf.. It. will nowI be seen thatwhem the links 622-.'and 69 are in then' fu'l'li line toggl'c-rpo-1 sition, and when. thebracket lo is: adjusted toa. posi-tion in closer proximity' to: thebracket 22,. the frame member 2T will be about the axis; ot the: pivot'bolts- 23; and.'l 24-l towards the.' right, andconsequentlyv theIspindle til'Y oi. the` caster wheel` support atA the'rear end;Y ofthefmower frame. will be' moved-towards the right side of the tractor..Incidentally; the cutter' bar; 39; wilt also be' swung. about theaxis'oi? the: pivot bolts 2% andi 2.5i, and the lea-d of, the cutter'bar will: tiflerebybe'increased.` On the: other hand,y adjustment of:thea bracket; 't6' towardsk the left of the. bracket'. bar." ls, thatis;,

farther away from theraxis. of' the pivot` bolts. 23

and 261, will' move' the spindle 33; of the caster wheel support.-towards: the' left' of. the tractor;4 and the lead' oi: the:v cutterbar' 39: will be. decreasedr by'suciiV adjustment' of the bracket 1%..After: the, spindle 3'3.' of' the caster wheel' support has; been.brought tothe. proper position, by adjustment of" the bracket i6;longitudinally of' the. hitch; bar l6 which will insure propertra/ckingl off the castery wheel 3l innormal opera-tiom the leadA ofithee cutter bar'may' be adjusted, if desiredpby an indetpendentadjusting mechanism or conventional construction which is operativelyinterposed` be.-K tween` the' cutter' bar yoke- (i8z and' the cutter."bar shoe 42, andwhich is'v generally indicatedy in'Fig. F,

5 by'the; reference character 981.

.f", ani'smV move from` the full line position to the` dotted! lineposition shown' in Fig. l, the. distance betweenV the upper drive shaft'{if} on the'v mower' frame' and the' power take-offshaft' I3 on thetractorbecomes shorter and such' shortenz ing of the distance' betweenthe 'twosflfraits` ac- Features and advantages of the present ihvenition will be apparent' from the foregoing d'e'- scription f anembodiment of the invention in a tractor mower; but it is to beunderstood that it isnot desired to limit the invention to theparticular forni and details described hereinabove and that theinvention includes such other forms and modications as are embraced bythe scope of the annexed claims.

It is claimed and desired to secure byLetters Patent:v Y

' 1. A mowercomprising a mounting structure adapted to support a cuttingmechanism positionable in'laterally disposed relation thereto, a hitchstructure for connecting said mounting structure with a source of draft,pivot means connecting said hitch and mounting structures with thelatter disposed in trailing, horizontally swingable relation to theformer, and a pair of pivotally connected links forming a toggle jointuniting portions of said hitchV and mounting structures spaced,respectively, horizontally sideward and horizontally rearward fromrsaidpivot means, and means operatively associated with said links and actingto maintain said links in a limiting position aording a predeterminedhigh initial resistance to a horizontal swinging movement of saidmounting structure relative to and toward said hitch structure.

2. A pull type mower comprising a frame struc- ,ture adapted to supporta cutting mechanism positionable in laterally disposed relation thereto,a hitch structure connectable in trailing relation to a source ofdraftpivot means connecting said hitch and frame structures with thelatter' disposed in trailing, horizontally swingable relation to theformer, a pair of pivotally connected links forming a toggle jointuniting portions of said hitch and frame structures spaced,

respectively, horizontally sideward and horizontally rearward from saidpivot means, and means operatively associated with said links andcontinuously acting to pull said links toward said hitch structure andinto a limiting position wherein said links act as a brace securing saidframe structure Vin releasably fixed, Atrailing relation to said hitchstructure.

i 3. A pull type mower comprising a frame structure adapted .to supporta cutting mechanism positionable in laterally disposed relation thereto,a hitch structure connectable in trailing'relation to a source of draft,pivot means connectg ing said hitch and frame structures with the latterdisposed in trailing, horizontally swingable relationto the former, apair of pivotally connected links forming a toggle joint unitingportions of said hitch and frame structures spaced, respectively,horizontally sideward and horizontally rearward from said pivot means,and means operatively associated lwith said links and continuouslyYacting .to pull said' links toward said hitch structure and into alimiting position approaching a straight vline relation forming one sideof agenerally triangular structure wherein said links act as a bracesecuring said frame structure-in releasably fixed, trailing relation tosaid hitch structure. Y v Y- 4. A pull type mower comprising a framestructure adapted to support a cutting mechanism' positionable inlaterally disposed relation thereto, a hitch structure connectable intrailing relation to a source of draft, pivot means connecting saidhitch and frame structures with the latter disposed in trailing,horizontally swingable relation to the former, a pair of pivotallyconnected links forming a toggle joint uniting portions of said hitchand frame structures spaced,

10 respectively,'horizontally sideward and horizontally rearward fromsaid pivot means, `and means operatively associated with said links andacting to retain said links in a limiting position wherein adapted formounting on a source of draft, a

frame structure pivotally connected at a first pivot center with saidhitch structure for horizontal swinging movement relative thereto, apair of-linksfpivotally connected with each other -at a second pivotcenter and with ysaid hitch and frame structures at third andfourthpivot centers, respectively, affording horizontal swingingmovement of said links and frame structure relative to each other andrelative to said hitch structure, resilient means associated with saidlinks in a manner operative to urge said links toward said hitchstructure and into a limiting position approaching a straight linerelation of the links, stop means for preventing said links fromovertraveling said limiting position-under the action of said resilientmeans, other stop means operative to limit movement of said framestructure about said irst pivot center in a direction toward said thirdpivot center, and cutting mechanism carried by said frame structure andpositionable in laterally disposed relation to the side thereof remotefrom said third pivot center so as to occupy a normal working positionwhile said links 3 are in'said limiting position.

ters, respectively, affording horizontal swinging movement of said linksand frame structure relative to each other and relative to said hitchstructure, stop means limiting movement of said links in a direction toposition said-second pivot center in close proximity to a straight lin-epassingl through said third and fourth pivot centers, resilient meansassociated with said links in a manner operative to urge said linkstoward said hitch structure and into a' limiting position as'determinedby said stop means, other stop means operative to. limitmovement of said frame structure about said lirst pivot center in adirection approaching said third pivot center, and cutting mechanismcarried by said frame structure and .said'hitch bar, a. pair of linkspivotallyconnected together and form-ing a toggle joint uniting aportion of said hitch bar disposed laterally out-- wardirom'said. otherside of said member'in horizontally'spaoed relation to said pivot con-1Vnection with a portion of. said member disposedl horizontally rearwardfrom said pivot connection, said frame member and links bei-nghorizontall-y swingable relative to each other and rela-- tive to said.hitch bar into a limiting position wherein. the pivot connection betweensaid linksis disposed immediately to. the rear of a straight linepassing( through. the portions of said links pivotall-y united. withsaid frame member and hitchbar, and means operatively associatedwithsaid. links for retaining same in said. limiting por-A sition aslong as the force tending to swing said frame toward said hitch barremains less than a predetermined amount, said means and links beingthereby operative tobrace and maintain said, frame member in releasablyiixed, trailing rela,-V tion to said. hitch bar.

8..- In a tractor-mower having. anelongated frame member andhaving acuttingmechanism operativelymountedon said member for horizontalswinging movement. in unison therewith and being, positionableto extendlateral-.ly out. ward:- from one side; ot said' member, an improvedbrealr-loacl: hitch means for connectingr said: frame,Y member intrailing relation. to a tractor and comprising a. hitch bar pivotallyconnected witrra portion of said mein-berm advance of.` said cuttingmechanism and. alording horizontal:

.swinging movement. of said member about a. gen.`

orally vertical axis aorded by said pivot. connec-l tion said hitchbarextending transversely of. said member andlaterally outward beyond theother side thereof, ay pairl of pivotal-ly connected: links forming atoggle: lointpivotally uniting a, portion. of said hitch disposed.laterally outward from said other side: of; said memberin horizontallyspaced relationV to said vertical axis witlr a,Y portion. of said framedisposed. l'iori'zon.-` tally rearward. from said verticalaxis, said.frame member and links being. horizontally sw-ingable relative. to eachother and'relative toI said hitch bar into.- a limiting positionwherein. the pivot connection between said links; is disposed` to therear or and adjacent a straight line passing through theA portions ofsaid links pivotallyunited' with said frame mem-ber' and hitch bar, andmeans operatively associated with saidi' links for retaining same in;said limitingA position as long asthe force tending-z toswing said'.frame. toward' saidhitch bar ren-latinsV less than apredetermned amount;said means andalinks being thereby oper.'- ative to. brace and maintainsaid frame.'v member Iijn releasably xed, trailinggrelation to saidhitch ar.. Y `V9. A tractor-mower* comprising an Velongated frame.member,. a..l cutting mechanism operatively mounted.. on said member forhorizontal. swing.- ng movement,` in unison therewith andi beingpositionableto extend laterally outward; from one 2 f side-A of said.member, Va hitch bar pivotally con nected, with a.. portion of: said:member in advance of said cuttingmeehanismfand' extending; laterallyoutward beyond the other side of Ysaid mem-V ber',A said pivotconnection aftording horizontal swinging movement of said memberrelative to:r said hitch bar, a pair of linkspivotallyconnected togetherand forming a toggle joint. uniting a portion of said hitch bar disposedlaterally outward from said other side of said member in horizontallyspaced relation to said pivot connection with a portion of said. memberdisposed horizon-tally` rearward from said pivot connection, saidframemember and links being. horizontally swingabl-e relative to each otherand relative to said hitch bar, resilient means opera-- tivelyassociated. with said links: and continuously acting to pull?. sametoward said hitch bar and into a, limiting position wherein saidf linksactY asa. brace securing said frame inreleasably fixed,

trailing relation to saidI bar.

10.. A tractor-mower comprising an. elongated; trame member, a cuttingmechanism operativehrA mounted on said member for horizontal swing,"V

. ing movement in unison therewith and being positionable.y to. extendlaterally outward from one Side of said member, a hitch.' bar pivotallyYconnected with a. portionoisaid member in. advance of saidY cuttingmechanism and'. extending latere?,

ally outward beyond the other side of said' memberr said pivotAconnection affording. horizontal: swingingA movement of said memberrelative to? said hitch bar, a pair of lin-ks pivotally connected.together and. forming atoggle joint unitingY an portion of said hitchbar disposed laterally out. ward from said other` side of said memberin. horizontally spaced relation. to said pivot. coni` nection with aportion o said member dsposed horizontally rearward from saidpivotconnec-4 tion. said frame member and links being hurt-- zontallyswi-ngableV relativev to' each other' and: relative to said. hitch bar,and resilient means operatively associated with' said links and con-1tinuously acting to pull same toward said. hitch. bar and into alimiting position. approaching a straight line relation, forming, oneysidef of; a generalily triangular structure; wherein said links act as abracesec-urinev sadi frame member. in release ably noted, trailing;relation to said hitch han 'l;"A.l\KlI;V

REFERENCES CITED The followingv references a-re of' record in the fileofthis patent:

